DairyNZ debunks mammary memory myth

DairyNZ debunks mammary memory myth

DairyNZ developer Jane Kay says the term 'mammary memory' is being bandied around the industry causing farmers to question their drying off decisions and continue milking when this might not be the best option.

“This statement is based on the premise that the cow’s mammary cells have a memory for low production and short lactation lengths. There is no truth behind this statement,” says Jane.

“Don’t worry about when the mammary cells go on holiday as most of them won’t be coming back.”

Jane says the cells in the mammary gland (or udder) are continuously changing.

“During the lactation, old, inactive cells die and new cells are formed. These two processes - cell death and cell formation, are constantly occurring and the rate at which they occur depends on factors such as stage of lactation and milking frequency.

“The balance between cell death and cell formation determines the number of cells in the udder and this affects milk production”.

After a pregnant dairy cow is dried off, the udder resets itself during the dry period. Old inactive cells continue to die and new cells form.

“This means the population of mammary cells changes markedly before the next lactation and there is no consequence of previous production on the next season,” says Jane.

“For example, when cows are milked once-a-day during one season and per cow production is reduced, there is no negative effect on milk production the following season.”

DairyNZ recommends dry off decisions for this season are made based on, achieving BCS targets, setting the farm up for the next lactation and the costs/benefits of milking on.